The present invention provides an improvement on the lock invention disclosed in my issued patent, U.S. Pat. No. 4,161,871 of July 24, 1979, and entitled, Locking Mechanism.
The present invention provides at least two rows of spring loaded pins disposed in a staggered side-by-side relationship in the outer cylinder, in combination with a pin bar provided, in the inner cylinder, with biased grooves therein, corresponding with biased grooves in the operating key, but in a reverse orientation therewith.
An outer anti-drill face plate protects the inner and outer cylinder, and the multiple rows of pins in the outer cylinder structure prevents the use of a blank key covered with wax or a like material to make an impression for the purpose of making a duplicate key. The first row of pins is contacted by the wax covered key and blocks the engagement thereof with the second or later rows of pins.
A double row of pins further provides for a minimum of six pins, three in each row, providing one fixed pin and five movable pins, one more than provided inconventional locks, resulting in a greater number of combinations.